Here I will share with you a wide range of shelters that are available. Some are quite basic and very inexpensive while others require a bit more of a financial investment. I would suggest starting very basic and making changes later.
1. A simple rubbermaid container that is insulated and stuffed with straw is a very basic and inexpensive shelter. A recommendation I have is to be sure there are 2 entrance holes. Feral cats often will not enter a shelter where there is not an escape door. If an intruder would enter the shelter, the cat needs a way to safely escape. The second hole can be a bit smaller than the first. You can also add a microwave heat disc to this shelter to help during very cold nights. Here is a link to some step by step instructions on how to make the shelter.
2. This next shelter, I call a Magic Box! I bought a Hefty or Sterlite clear storage container from Target. It is 23″ L x 16″ W x 13″ H. I love that it is clear so that I can see in it easily. I made one entrance in the front and one on the side. I covered the plastic edges with duct tape as they were a bit sharp. I lined the lid, and all sides with Reflectix insulation that I bought in a roll at Home Depot. I used duct tape to keep it in place. I then added an electric heat pad to the bottom. I use the K&H extreme weather kitty pad which fits perfectly in the bottom. Just be sure to cut out a notch in the back for the cord. Here are two pictures. For more pictures on shelters please see my Flickr site.
3. K&H Outdoor Heated Cat House: This is another option if you do not want to build anything, but still want a shelter that withstand the elements. I have 2 of these and have used them in a variety of locations. You can order the house with or without the heat pad. If you use them out in the open, they will get wet inside, but they work perfectly when under a deck or other covering. I also like that you can take the sides down. I put two of these next to each other and opened the sides so the cats could snuggle together. Here is a link to the shelter. I have one picture of Shadow and Stellar using the heated houses when they are side by side and the side flaps down. You can see it below. You also can find pictures of this on my Flickr site.
4. This next shelter requires either purchasing the shelter from Feral Villa or building your own. My wonderful husband and son built this for Shadow and then modified it a few years later to add a window and remove part of the wind break. With this shelter you can stuff it with straw or place a heat pad inside. It has an entrance and an exit for safety as well as a wind break. The lid is hinged for easy opening to clean. This shelter is not very big inside. My two ferals cannot both fit comfortably inside. This shelter was built when Shadow was first here, but he never took to it. Unfortunately a raccoon did! I do use this shelter outside on a table and during bitter cold nights, I leave a small amount of dry cat food inside. On occasion one of the ferals will get inside and rest for a short time. You can find information on how to build this shelter on Alley Cat Allies. It is called Alley Cat Allies Inexpensive Cat Shelter. There are also other instructions on this site for building other types of shelters Here is a link to Feral Villa shelters. Here are two pictures of the shelter my husband and son built. You can also view more pictures of this shelter on my Flickr site.
5. Shelter Logic Shed in a Box and Heated Cat House: During the spring, summer and early fall months, I have a retractable canopy on my deck that works perfectly to keep the cats out of the elements. They have an outdoor love seat that they sleep on underneath the canopy. During the late fall and winter, the canopy must be taken down as it cannot withstand snow. I really wanted a shelter on my deck that I could see the cats using as well as knowing the cats were safe. I found a Shelter Logic Shed in a Box that is 6’x6′. It looks similar to a tent, but does not have a bottom and the material is very thick and durable. This winter (2016-2017) is my 6th winter with this shelter and it is still in great shape. Here is a link. It takes a few hours to put together, but the best thing is that it can be taken down and stored during the warmer months.
The first winter that used the Shelter Logic tent, I only had the outdoor love seat with two outdoor heat pads. It was a very mild winter that year. The next year I purchased the K&H Outdoor Heated Kitty House. The cats did well with these. The 3rd winter with this shelter I needed to make a few modifications. The cats would not stand for me putting the front flap down all the way. It was a must for them to see out and be able to get out easily. I was able to put the flap about 1/2-2/3 of the way down. I also noticed a lot of wind came up from the bottom of the deck. We purchased plywood that was painted with outdoor weathering paint and then topped with astroturf. What a difference the flooring made. This also made it more comfortable for me to go out and sit with the cats.
I still wished they had a warmer cat house. During January of 2014 we had the Polar Vortex with lows of -20 and wind chills of -35. My husband and son designed a fairly large heated cat house with a large window for them to see out. It was insulated with Reflectix. To heat the cat house, a light socket was installed and a red reptile 100w bulb was used. To cover the bulb an old paint can was painted black and holes poked all around it. The bulb put out a lot of heat. I kept a thermometer inside and it stayed above 40 degrees. Of course I worried about the light bulb and the chance of it catching on fire or the chance of it burning out. I decided to upgrade to the hound heater. It is used in outdoor dog and cat houses and has a temperature controlled setting. I purchased the Hound Heater Deluxe. This product is amazing. We had another terrible cold snap with -15 and wind chills of -30. The heated house did not drop below 30. My cats love this. Here are a few pictures of it this season with one showing the inside of the heated house. To see other pictures please see my Flickr site. Here is a link to a blog post with directions on how to make the heated house.
Here is a picture from November 2015 with two heated houses.
6. Feeding Stations: While not a shelter, a feeding station or two is necessary when feeding feral cats. You can use something very similar such as a rubbermaid container on its side or you can purchase or build a sturdier structure. I started off using a rubbermaid container, but even when I had bricks inside and on top, the wind found a way to blow it away. My husband and son have now built 3 feeding stations. They are deep enough to keep the food completely dry and they are large enough that more than one cat can fit inside. Here is a link to purchasing a feeding station or you can easily build one yourself. Below is a picture of the rubbermaid container as well as the ones my cats currently use.